In a publication entitled "Using PC Storyboard", Information Update SN60-1796, November 1985, published by the IBM Corporation, Armonk, N.Y., there is described at pages 85-88 the functionality of a zoom, or image magnification, function for an applications program entitled "PC Storyboard". While providing for individual pel, or pixel, enlargement this prior art zoom function does not center the the zoom function at the cursor position upon the display screen. This prior art zoom function also does not scroll a zoom viewport that displays an unmagnified view of the zoomed image portion.
It is thus an object of the invention to provide a zoom function that centers the magnified portion of a visual image upon a display cursor.
It is another object of the invention to provide a zoom function having a viewport that scrolls through an image as a cursor is moved.